Purpose and Advantages
Packet radio is the fourth major digital radio communications mode. Earlier modes were telegraphy (Morse Code), teleprinter (Baudot) and facsimile. Like those earlier modes, packet was intended as a way to reliably transmit written information. The primary advantage was initially expected to be increased speed, but as the protocol developed, other capabilities surfaced.
By the early 1990s, packet radio was not only recognized as a way to send text, but also to send files (including small computer programs), handle repetitive transmissions, control remote systems, etc.
The technology itself was a leap forward, making it possible for nearly any packet station to act as a digipeater, linking distant stations with each other through ad hoc networks. This makes packet especially useful for emergency communications. In addition, mobile packet radio stations can automatically transmit their location, and check in periodically with the network to show that they are still operating.
The most common use of packet is in amateur radio, to construct wireless computer networks. Packet radio uses the AX.25 (Amateur X.25) data link layer protocol, derived from the X.25 protocol suite and adapted for amateur radio use. AX.25 was developed in the 1970s and is based on the wired network protocol X.25. AX.25 includes a digipeater field to allow other stations to automatically repeat packets to extend the range of transmitters. One advantage is that every packet sent contains the sender's and recipient's amateur radio callsign, thus providing station identification with every transmission.
Read more about this topic: Packet Radio
Famous quotes containing the words purpose and/or advantages:
“God sent children for another purpose than merely to keep up the race—to enlarge our hears; and to make us unselfish and full of kindly sympathies and affections; to give our souls higher aims; to call out all our faculties to extended enterprise and exertion; and to bring round our firesides bright faces, happy smiles, and loving, tender hearts.”
—Mary Botham Howitt (20th century)
“If we help an educated man’s daughter to go to Cambridge are we not forcing her to think not about education but about war?—not how she can learn, but how she can fight in order that she might win the same advantages as her brothers?”
—Virginia Woolf (1882–1941)